[PATCH v3] usb: host: ehci-platform: add support for optional external vbus supply

[Amelie DELAUNAY]

Hi Robin,

On 02/28/2018 02:33 PM, Robin Murphy wrote:
> Hi Amelie,
> 
> Just a couple of drive-by coding style comments...
> 
> On 23/02/18 13:46, Amelie Delaunay wrote:
>> On some boards, especially when vbus supply requires large current,
>> and the charge pump on the PHY isn't enough, an external vbus power switch
>> may be used.
>> Add support for optional external vbus supply per port in ehci-platform.
>>
>> Signed-off-by: Amelie Delaunay <amelie.delaunay at st.com>
>>
>> ---
>> Changes in v3:
>>    * Address Felipe Balbi comments: reduce indentation in
>>      ehci_platform_port_power.
>>    * Address Roger Quadros and Alan Stern comments: platforms can have one
>>      external vbus supply per port, so add support to get as many optional
>>      regulator as implemented ports on the host controller.
>>
>> Changes in v2:
>>    * Address Roger Quadros comments: move regulator_enable/disable from
>>      ehci_platform_power_on/off to ehci_platform_port_power.
>> ---
>>    Documentation/devicetree/bindings/usb/usb-ehci.txt |  1 +
>>    drivers/usb/host/ehci-platform.c                   | 52 +++++++++++++++++++++-
>>    2 files changed, 52 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/devicetree/bindings/usb/usb-ehci.txt b/Documentation/devicetree/bindings/usb/usb-ehci.txt
>> index 3efde12..cd576db 100644
>> --- a/Documentation/devicetree/bindings/usb/usb-ehci.txt
>> +++ b/Documentation/devicetree/bindings/usb/usb-ehci.txt
>> @@ -19,6 +19,7 @@ Optional properties:
>>     - phys : phandle + phy specifier pair
>>     - phy-names : "usb"
>>     - resets : phandle + reset specifier pair
>> + - portN_vbus-supply : phandle of regulator supplying vbus for port N
>>    
>>    Example (Sequoia 440EPx):
>>        ehci at e0000300 {
>> diff --git a/drivers/usb/host/ehci-platform.c b/drivers/usb/host/ehci-platform.c
>> index b065a96..8e9f201 100644
>> --- a/drivers/usb/host/ehci-platform.c
>> +++ b/drivers/usb/host/ehci-platform.c
>> @@ -29,6 +29,7 @@
>>    #include <linux/of.h>
>>    #include <linux/phy/phy.h>
>>    #include <linux/platform_device.h>
>> +#include <linux/regulator/consumer.h>
>>    #include <linux/reset.h>
>>    #include <linux/usb.h>
>>    #include <linux/usb/hcd.h>
>> @@ -46,6 +47,7 @@ struct ehci_platform_priv {
>>    	struct reset_control *rsts;
>>    	struct phy **phys;
>>    	int num_phys;
>> +	struct regulator **vbus_supplies;
>>    	bool reset_on_resume;
>>    };
>>    
>> @@ -56,7 +58,8 @@ static int ehci_platform_reset(struct usb_hcd *hcd)
>>    	struct platform_device *pdev = to_platform_device(hcd->self.controller);
>>    	struct usb_ehci_pdata *pdata = dev_get_platdata(&pdev->dev);
>>    	struct ehci_hcd *ehci = hcd_to_ehci(hcd);
>> -	int retval;
>> +	struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
>> +	int portnum, n_ports, retval;
>>    
>>    	ehci->has_synopsys_hc_bug = pdata->has_synopsys_hc_bug;
>>    
>> @@ -71,11 +74,57 @@ static int ehci_platform_reset(struct usb_hcd *hcd)
>>    	if (retval)
>>    		return retval;
>>    
>> +	n_ports = HCS_N_PORTS(ehci->hcs_params);
>> +	priv->vbus_supplies = devm_kcalloc(&pdev->dev, n_ports,
>> +					   sizeof(struct regulator *),
> 
> Using "sizeof(*priv->vbus_supplies)" here will prevent people sending
> annoying cleanup patches later.
> 

OK, I will fix it in v4.

>> +					   GFP_KERNEL);
>> +	if (!priv->vbus_supplies)
>> +		return -ENOMEM;
>> +
>> +	for (portnum = 0; portnum < n_ports; portnum++) {
>> +		struct regulator *vbus_supply;
>> +		char id[20];
>> +
>> +		sprintf(id, "port%d_vbus", portnum);
>> +
>> +		vbus_supply = devm_regulator_get_optional(&pdev->dev, id);
>> +		if (IS_ERR(vbus_supply)) {
>> +			retval = PTR_ERR(vbus_supply);
>> +			if (retval == -ENODEV)
>> +				priv->vbus_supplies[portnum] = NULL;
> 
> The array element here hasn't yet been assigned to since kcalloc()
> initially zeroed it, so this is entirely redundant - you can simply make
> the comparison a "!=" and remove the "else" case.
> 
> Robin.
> 

Thanks for spotting this! Fix in v4.

Amelie

>> +			else
>> +				return retval;
>> +		} else {
>> +			priv->vbus_supplies[portnum] = vbus_supply;
>> +		}
>> +	}
>> +
>>    	if (pdata->no_io_watchdog)
>>    		ehci->need_io_watchdog = 0;
>>    	return 0;
>>    }
>>    
>> +static int ehci_platform_port_power(struct usb_hcd *hcd, int portnum,
>> +				    bool enable)
>> +{
>> +	struct ehci_platform_priv *priv = hcd_to_ehci_priv(hcd);
>> +	int ret;
>> +
>> +	if (!priv->vbus_supplies[portnum])
>> +		return 0;
>> +
>> +	if (enable)
>> +		ret = regulator_enable(priv->vbus_supplies[portnum]);
>> +	else
>> +		ret = regulator_disable(priv->vbus_supplies[portnum]);
>> +	if (ret)
>> +		dev_err(hcd->self.controller,
>> +			"failed to %s vbus supply for port %d: %d\n",
>> +			enable ? "enable" : "disable", portnum, ret);
>> +
>> +	return ret;
>> +}
>> +
>>    static int ehci_platform_power_on(struct platform_device *dev)
>>    {
>>    	struct usb_hcd *hcd = platform_get_drvdata(dev);
>> @@ -134,6 +183,7 @@ static struct hc_driver __read_mostly ehci_platform_hc_driver;
>>    static const struct ehci_driver_overrides platform_overrides __initconst = {
>>    	.reset =		ehci_platform_reset,
>>    	.extra_priv_size =	sizeof(struct ehci_platform_priv),
>> +	.port_power =		ehci_platform_port_power,
>>    };
>>    
>>    static struct usb_ehci_pdata ehci_platform_defaults = {
>>